Unroll.me CEO and founder Jojo Hedaya, in a blog post responding to the outcry after Mike Isaac of The New York Times revealed that the company does things like sell “anonymized” Lyft receipts to Lyft arch-rival Uber:

Our users are the heart of our company and service. So it was
heartbreaking to see that some of our users were upset to learn
about how we monetize our free service.

And while we try our best to be open about our business model,
recent customer feedback tells me we weren’t explicit enough.

Give me a fucking break. They’re not “heartbroken” because their users are upset. They’re in damage-control mode because they were operating under the radar and now they’ve been revealed, very publicly, as the shitbags that they are. If you’ve signed up for Unroll.me, delete your account. They make money by selling your purchase receipts to the highest bidder. That’s their business.

I worked for a company that nearly acquired unroll.me. At the
time, which was over three years ago, they had kept a copy of
every single email of yours that you sent or received while a part
of their service. Those emails were kept in a series of poorly
secured S3 buckets. A large part of Slice buying unroll.me was for
access to those email archives. Specifically, they wanted to look
for keyword trends and for receipts from online purchases.